Ellipsograph.



No. 7|7,082. Piatented Dc. 30, |902.

E. N. DART.. .ELLIPSOGBAPIL (Application. led May 26, 1902.)

(No Model.)

Fir

lliTn STATES PATENT OFFICE.

EDWARD N. DART, OF NEW YORK, N. Y.

ELLlPSOGRAPl-l.

SPECIFICATION forming part of Letters Patent No. 717,082, dated December30, 1902.

Application led May 26, 1902. Serial No. 108,978. (No model.)

To all whom it may concern:

Be it known that I, EDWARD N. DART, a citizen of the United States ofAmerica, and a resident of New York city, borough of Manhattan, countyand State of New York, have invented certain new and useful Improvementsin Ellipsographs, of which the following is a specification.

The object of my invention is to produce an instrument with which anentire ellipse can be drawn at one operation and that shall be capableof ready adjustment, whereby ellipses of a considerable range ofeccentricity and size can be drawn.

The instrumentis of the well-known traminel form, in which two points ina beam are guided by two intersecting trams, the ellipse being describedby a third point on the beam.

Such instruments have heretofore been limited in their range ofadjustment by reason of the fact that the tram for the minor aXis of theellipse will lie across the line of the ellipse if the ellipse is at allnarrow, so that the portions of the ellipse which adjoin this axiscannot be drawn with the instrument and must be patched out by the useof curves after the instrument has been removed from the paper. lilyinvention avoids this (lifticulty by providing a sliding or telescopictram for the minor axis of the ellipse.

In the accompanying sheet of drawings, which form a part of thisapplication, Figure 1 is a plan view of the instrument. Fig. 2 is an endView, and Fig. 3 is a side view.

A base A carries a tram B B and supports a tram C, which is free toslide transversely of the tram B and is therefore not rigidly attachedor formed on the base, but is guided in a slot through the base at rightangles to the tram B and is free to slide in this slot. A slide D isguided by the tram B, and a block E is swiveled to this slide by a pinF. The block E slides on a scribingbeam G and is clamped to the beam atthe desired point, depending on the size ofthe ellipse to be scribed,byascrew L. rlhe point on the beam at which the block is clamped andwhich is opposite the pin F is therefore conned in its movement to astraight line in the direction ofthe slide D. At one end of theseribing-beam is a pin H, which slides along aslot I, With closed ends,in the tram C, and is therefore conned in its movement to a straightline in the direction of this tram. Its movement, however, is notlimited by the length of this slot, for if the scribiug-beam is broughtto the position shown by the dotted lines U U the pin H on reaching theend t' of the tram C will slide this tram transversely of the other tramB, and the pin Will continue its movement in the direction of the tram Cand be guided by this tram. At a third point on the scribingbeam is thedrawingpointJ,Whichis clamped to the beam by a screw K. This may beeither a drawing-pencil m or a drawing-pen n, as shown in Fig. 2. Theupper end of the drawing-point is provided With a handle, which isswiveled at 7L. In order that the instru ment may be `packed in asmaller compass, the beam is jointed at M. Near each end of the base Aare pins N, which are clamped in place by the screws O. The points ofthese pins are protruded through the bottom of the base and into thepaper or draw ing-board sufleiently to hold the instrument in place.

Having determined upon the length, Width, and location of the ellipse tobe drawn, the drawing-point J is set on the scribing-beam at a distancefrom the pin H equal to half the major axis of the ellipse, and theblock E is set at a distance from the pin H equal to the differencebetween half the major and the minor axes ofthe ellipse. Thescribing-beam is provided with a graduated scale by which thedrawing-point and the block can be adjusted by bringing the notches Rand X to the proper marks on the scale. The notch in the block `is atone side of the swivel-pin F, and the notch in the block carrying thedrawing-point is at an equal distance to one side of the point directlyover the drawing-point. In order that these blocks may be set properlyby reading the scale at these notches, the scale-divisions are eachplaced on the beam nearer to the pin H by the amount that these notchesR and X are to one side, respectively, of the drawing-point and theswivel-pin. The base ot' the instrument is set on the drawingpaper sothat its tram B B will lie over the major axis and its tram C will lieover the minor axis of the ellipse to be drawn. The

handle of the drawing-point is then seized by the fingers and theellipse is drawn.

What I claim as new, and desire to secure Signed by me, in New Yorkcity, borough by Letters Patent of the United States, is of Manhattan,New York, this 23d day of May,

In an ellipsograph, the combination of two 1902.

intersecting trams, one of which is free to EDWARD N. DART. 5 slidetransversely of the other tram, and a Witnesses:

scribing-beam with points guided by each SAMUEL W. BALCH,

tram, substantially as described. i EDWARD J. MURPHY.

